The present invention is directed to mold apparatus for the injection molding of plastic parts, such as plastic lids. The injection molding of plastic parts and plastic lids is well known in the art. When the desired part includes an in-turned flange or lip, the mold is more complicated and often includes inserts or slides.
In my copending application entitled "Tamper Resistant Lid ", Ser. No. 08/361,297, filed Dec. 22, 1994, a plastic lid is disclosed which includes a top, a downwardly extending skirt and a series of inwardly directed locking ribs, which are circumferentially spaced on the interior of the skirt. Such a plastic lid is illustrated in FIG. 1 of the present drawings.
The present injection mold apparatus and method is directed to a mold apparatus and method which forms a thermoplastic, such as a low or high density polyethylene into the desired plastic lid.
The injection mold apparatus and method of the present invention provide an improvement over that known in the art. The improved mold apparatus allows complex-shaped parts with good dimensional accuracy. The present apparatus and method provides an interior flange on the plastic lid and facilitates the production of such lids at a high production rate.